/* 隐藏所有幻灯片，除了第一张 */
.slide {
    margin: auto;
    display: none;
}

.slide:first-child {
    display: block;
}

/* 控制按钮的样式 */
.control {
    display: block;
    width: 50px;
    height: 50px;
    font-size: 2em;
    position: absolute;
    top: 250px;
    margin-top: -25px;
    text-align: center;
    line-height: 50px;
    background-color: rgba(0, 0, 0, 0.5);
    color: #fff;
    text-decoration: none;
}

.prev {
    left: 0;
}

.next {
    right: 0;
}

